sox: convert license format to SPDX

Signed-off-by: Ian Leonard <antonlacon@gmail.com>
lame: convert license to SPDX format

Signed-off-by: Ian Leonard <antonlacon@gmail.com>
mpc: add PKG_LICENSE information

Signed-off-by: Ian Leonard <antonlacon@gmail.com>
pulseaudio: add PKG_LICENSE information

Signed-off-by: Ian Leonard <antonlacon@gmail.com>